Batteries (electric cells) are generally classified into two types, such as a primary battery and a secondary battery which is possible to be charged or discharged, among which, a large capacity battery is comprised of a structure using an electrolyte.
Since an electrolyte is usually in the form of a solution, it should be provided with several safety devices. Firstly, the electrolyte should not be leaked out, while gases generated by chemical reactions should be emitted outside in order to prevent explosion of a battery. Generally, such functions are achieved by a battery case cover which covers an electrolytic bath (battery case) containing an electrolyte.
FIG. 1 is a perspective view showing a battery equipped with a conventional battery case cover. Referring to FIG. 1, conventional batteries are generally comprised of an electrolytic bath (130) where an electrolytic solution is charged and a battery case cover (140) covering the electrolytic bath (130).
The battery case cover (140) is comprised of two different regions of an upper cover (120) and a lower cover (110) where a terminal (50) and a handle receiving part (40) are formed.
FIG. 2 is a plan view of a conventional battery case cover, showing an upper cover (120) and a lower cover (110) in disassembled state.